large
Architecting
node.js
applications
Monday, October 22, 12

@sergimansilla
Monday, October 22, 12

P ro g ra m
☐ C l o u d9 ID E?
☐ Grow in g pai n s
☐ I n t ro du c i n g Arc hitec t
☐ Le ss on s le arn e d
Monday, October 22, 12

Normal developers
Monday, October 22, 12

JavaScript Developer
Monday, October 22, 12

Cloud9 IDE - http://c9.io
Monday, October 22, 12

Real
debugging
Monday, October 22, 12

(Smart!)
Code completion
Monday, October 22, 12

Static
analysis
Monday, October 22, 12

Free
Linux
Monday, October 22, 12
VM

Bring your own machine
Monday, October 22, 12

Real terminal
Monday, October 22, 12

Collaboration
Monday, October 22, 12

See each other type
Debug together
Productivity++
Monday, October 22, 12

Create
Deploy Run/Debug
Share Test
Monday, October 22, 12

P ro g ra m
☑ C l o u d9 ID E?
☐ Grow in g pai n s
☐ I n t ro du c i n g Arc hitec t
☐ Le ss on s le arn e d
Monday, October 22, 12

10,000s
LOC
of JavaScript
Monday, October 22, 12

dynamic,
weakly
typed
language
Monday, October 22, 12

one
single
Monday, October 22, 12
thread

Openshift
Cloud9 datacenter
Remote VM
IDE server Remote VM
Remote VM
Monday, October 22, 12

Pure madness
Monday, October 22, 12

Modularization
Monday, October 22, 12

Black
box
coding
Monday, October 22, 12

Monday, October 22, 12

Java/.NET import(s)
Node.js require
Monday, October 22, 12

Great for
re
requi
abstracting
Monday, October 22, 12
away

re
requi
Not Great for
application
modularity
Monday, October 22, 12

re
requi
Relies on FS
duplicated modules
maps to folder names
Hard to configure module
Monday, October 22, 12

Dependency error handling
coding time compile time run time
!
OM
- BO
KA
- Server crash
- Unhappy customers
- Developer gets fired
Monday, October 22, 12

How to fix it?
Static dependency list Resolve at startup
Named services No FS required
Easy configuration Pass an object
Monday, October 22, 12

P ro g ra m
☑ C l o u d9 ID E?
☑ G row i n g pai n s
☐ I n t ro du c i n g Arc hitec t
☐ Le ss on s le arn e d
Monday, October 22, 12

Architect
github.com/c9/architect
Monday, October 22, 12

Architect
Everything is a plugin
Plugins can consume plugins
An application is just a set of plugins
Monday, October 22, 12

Dependency model
require runtime
Architect compile time
Monday, October 22, 12

Dependency error handling
Architect
coding time compile time run time
- Happy customers
- Fails before release - Developer keeps job
Monday, October 22, 12

Monday, October 22, 12

Declare entity ‘presenter’ with behavior
Use ‘presenter’ to do a presentation
Monday, October 22, 12

Dependency model
Presenter Presentation
Monday, October 22, 12

Express our model
package.json
Builds dependency tree
without
executing code
Monday, October 22, 12

Monday, October 22, 12

What’s next?
Wrap in Architect plugin code
Extract the code
Make two plugins
Monday, October 22, 12

Function
signature
Call when done
Monday, October 22, 12

Architect plugin code
Module.exports
Options - we’ll get to that
Imports - everything you ‘consume’
Register - invoke when done
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

Easy to test
Mock dependencies
Monday, October 22, 12

Assert ‘dance’ is called 11 times
Monday, October 22, 12

No black magic
Specify dependency model
Feed architect a config file
Call ‘createApp’
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

Configuration
Per-plugin options
No global options object
Specify in config file
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

Options
Automatically passed in at startup
Options are also dependencies
Fail if options aren’t present
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

Architect makes you think of your app as
chunks of functionality
rather than sets of classes
Monday, October 22, 12

Think ‘chunks of functionality’
Implicit type constraints
Keep implementation private
Swap features instead of interfaces
Monday, October 22, 12

How does Cloud9 use it?
Open source version
Local version (OS + sync)
Hosted version
Normal
FTP
SSH
Monday, October 22, 12

Monday, October 22, 12

Swap feature per
implementation
On Open source: talk local filesystem
On FTP: talk FTP library
On SSH: talk via a SSH bridge
Monday, October 22, 12

Here is something your
DI framework can’t do
Monday, October 22, 12

Single node.js process
IDE instance IDE instance
(FTP) (SSH)
Other code
(dashboard etc.)
IDE instance IDE instance
(Normal) (Normal)
Monday, October 22, 12

Monday, October 22, 12

Architect can do
Multiple instances of same plugin
Run independently
But in the same process
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

HERE’S SOMETHING COOL
Monday, October 22, 12

Centralized eventbus
Loose coupling between plugins
No hard dependencies!
Can also do inter-context communication
Monday, October 22, 12

React on event
Other plugin
Event
bus
Emit event
Plugin
Monday, October 22, 12

Monday, October 22, 12

Monday, October 22, 12

And now scale up
Need something inter-server
Swap it with i.e. Redis PubSub
Plugins will never notice
Modular awesomeness!
Monday, October 22, 12

P ro g ra m
☑ C l o u d9 ID E?
☑ G row i n g pai n s
☑ I n t ro du c i n g Arc hitec t
☐ Le sson s learn ed
Monday, October 22, 12

Modularize in feature blocks
Don’t over engineer
Don’t create too small blocks
They aren’t interfaces!
Monday, October 22, 12

Use dependency injection
Architect (JavaScript)
StructureMap (.NET)
Spring (Java)
Monday, October 22, 12

Avoid context switching
Less code!
Less errors!
Less boilerplate!
Monday, October 22, 12

Loose coupling
Use an event bus
Smaller dependency graph
Monday, October 22, 12

github.com/c9/architect
Monday, October 22, 12

Happy coding!
Monday, October 22, 12

http://c9.io
Sergi Mansilla
@sergimansilla
github.com/sergi
Monday, October 22, 12